Sequential Isomerization of a Macrocyclic Polyoxometalate Archetype.

Controlled isomerization of individual {α-PWO} polyoxotungstate building blocks under the constricted conditions of the macrocyclic [PWO] archetype ({PW}) is linked to site-specific Cu coordination. The derivatives [-PWO{Cu(HO)}] (), [-PWO{Cu(HO)}] (), and [-PWO{Cu(HO)}] () feature the {αγαγ-PW} and the hitherto unknown {-PW} and {-PW} isomers based on {α-PW} and/or Cu-stabilized {γ-PW} units and form from the reactions of the classical {PW} (={-PW}) and CuCl in sodium acetate medium (pH 5.2). All products were thoroughly characterized in both the solid state and aqueous solutions, including electrocatalysis assessments.